It has long been the practice in the hard rock mining industry to employ drill bits which are machined from bar to produce an integral drill bit body and head section. Such drill bits usually include internal fluid passageways for carrying flushing fluid to the working face of the drill bit and also flutes around the periphery of the drill bit to carry flushing fluid away from the working face to clean the hole.
In currently used drill bits of this type, the working face of the head section includes carbide cutting inserts, usually referred to as carbide buttons. The carbide buttons are press-fitted into blind bores drilled in the working face of the drill bit. The carbide buttons can be sharpened a limited number of times to maintain the drilling efficiency of the bit. However, the carbide buttons eventually wear or break to the point that further sharpening has little or no effect. When this occurs, the entire drill bit is discarded since it is impossible to replace the carbide buttons. A drill bit designed to permit replacement of the carbide buttons would eliminate the waste associated with past practice.
Drill bit assemblies have been proposed in the past in which the carbide cutting elements are replaceable. However, these designs have apparently been unacceptable in drill bits used with in-the-hole drilling equipment. One important consideration is that the carbide inserts have a relatively simple shape which corresponds generally to the shapes currently manufactured in the carbide tool industry.